The present invention relates to an image forming apparatus using electrophotographic technology.
Image forming apparatuses such as a copier, a facsimile machine or a printer using electrophotographic technology are widely used. Such an image forming apparatus performs a charging process to uniformly charge a surface of an image bearing body such as a photosensitive drum, an exposure process to expose the surface of the image bearing body with light to form a latent image, a developing process to develop the latent image using a developer to form a developer image on the image bearing body, a transfer process to transfer the developer image to a medium such as a paper, and a fixing process to fix the developer image to the medium.
Recently, there has been developed an image forming apparatus including a process unit and an apparatus main body to which the process unit is detachably mounted. The process unit includes several units for performing the above described processes (for example, the image bearing body, a charging unit that performs the charging process, and a developing unit that performs the developing process). The process unit can be easily detached or replaced, for example, when operation failure of the image forming apparatus occurs or when maintenance of the image forming apparatus is to be performed. An example of such an image forming apparatus is disclosed in, for example, Japanese Laid-open Patent Publication No. 2006-78542 (see FIG. 3 and paragraphs 0014-0016).
The image forming apparatus disclosed in the above described publication includes an apparatus main body, a process unit (i.e., a process cartridge) detachably mounted to the apparatus main body, a cover member rotatably provided on the apparatus main body, and an optical head mounted on an inner side of the cover member. When the cover member is in a position to close an upper part of the apparatus main body, a light emitting surface of the optical head faces a surface of a photosensitive drum (i.e., the image bearing body) provided in the process unit. When detaching the process unit from the apparatus main body, the cover member is rotated so as to open the upper part of the apparatus main body, and then the process unit is taken out from the apparatus main body. In other words, the process unit is configured as a replaceable unit.
However, in the conventional image forming apparatus, operability in detaching or replacing the replaceable unit (i.e., the process unit) is not sufficient.